Multi-Band Reconfigurable All-Digital RF Transmitter

5G has always been regarded as the cornerstone of the industry’s digital and intelligent transformation,and 5G-Advanced,as an important intermediate node between 5G and 6G,has a flexible network architecture and develops in a flexible and reconfigurable direction.Continuous/non-continuous carrier aggregation is the key to 5G.Therefore,it is of great significance to develop a radio transceiver that is flexible,reconfigurable,and supports multiband and multi-standard transmission.The traditional method of implementing multi-band transmission in analog communication systems is to design different circuits for different bands,which leads to increased equipment area,increased cost,and increased power consumption while being limited in terms of scalability,configurability,and flexibility.All-digital RF transmitters have shown great potential in the design of next-generation RF transceiver systems,but the problems of spectral aliasing and noise interference in multi-frequency concurrent transmission lead to system performance degradation,so multi-band transmission is still the technical bottleneck of current all-digital transceivers.Aiming at this problem,this paper studies and designs a multi-band reconfigurable all-digital RF transmitter,and takes this as the research focus.The main work is as follows:First,the all-digital transmitter architecture and its key technologies are introduced,and the research status of multi-band digital transmitters,broadband digital transmitters and key modular quantization modulators is analyzed.It is concluded that the current modulators have problems such as poor transmission performance,complex structure,and system instability in multi-band transmission.Second,Aiming at the problems of poor performance,complex structure,and unstable system of the current Delta-Sigma modulator in multi-band transmission,a band-reconfigurable Delta-Sigma based on The Sturdy Multi-st Age noise-Shaping(SMASH)is proposed.The single-stage modulation module is used as the basic unit,and the multiplexing and expansion are carried out to realize the multi-band reconfigurable Delta-Sigma modulation architecture.This architecture enables a flexible frequency band,and the function of the operating frequency of each frequency band is flexible and has good scalability and stability.The multiplexing process of the single-band Delta-Sigma adjustment period to dual-band Delta-Sigma is analyzed,and then the structural characteristics and noise transfer function of the multi-band Delta-Sigma are summarized.The realization principle and multiplexing method of the reconfigurable multi-band delta-sigma modulator is disclosed,and the transmission problem of discontinuous frequency spectrum aggregation in which the structure of the high-order deltasigma modulator is unstable and multi-carrier is easy to interfere is solved.Thirdly,based on the Delta-Sigma modulator with a reconfigurable frequency band,a fully digital RF transmitter with a reconfigurable frequency band is designed to meet the requirements of multi-standard,multi-bandwidth,and multi-band transmission of the current communication system.The transmitter system can simultaneously transmit multiple independent baseband signals to meet the requirements of multi-standard,multi-bandwidth,and multi-band systems,and the multi-channel carrier signals are independently controllable,flexible,and real-time adjustable.The all-digital transmitter system is built and modeled and simulated to confirm the correctness of the system architecture design and algorithm function,and then realize the dual-band reconfigurable all-digital RF transmitter system on the Field Programmable Gate Array(FPGA)development platform,and analyze circuit synthesis diagrams,resource usage and timing reports.The full test analysis of the full digital transmitter system is performed by the Integrated Logic Analyzer(ILA),and the feasibility of all digital transmitter system hardware is authenticated.Fourth,an all-digital RF transmitter test platform is built,and a spectrum analyzer is used to perform spectrum analysis on the RF output signal.The single-band function switching of the dual-band reconfigurable all-digital transmitter is performed through the switch gating module.The system functions are tested from different application scenarios to verify the feasibility of the hardware architecture of the dual-band reconfigurable all-digital RF transmitter system in this paper.The experimental results show that the switch gating module can realize the free switching of the transmission function of the all-digital transmitter in singleband and dual-band.The working frequency of the all-digital transmitter system can reach6.4GHz,the two baseband signals are independent of each other,the two channels of the carrier wave can be adjusted arbitrarily from 0 to 3.2GHz,and the output signal has good performance indicators.The adjacent channel leakage ratio(ACLR)values are below-30 d Bc,and the error vector magnitude(EVM)values are below 5%.The dual-frequency reconfigurable all-digital transmitter system meets the high-performance transmission requirements of current wireless communication systems for multi-standard,multi-bandwidth,and multi-band.